1. Field of the Invention
This invention generally relates to photographic lighting apparatus and has particular reference to an improved multiflash unit having integral means for optically controlling the light produced by the flashlamps.
2. Description of the Prior Art
Multiflash units which contain four flashlamps mounted on a substantially square-shaped plastic base member that has an integrally formed post or jack holder which permits the unit to be inserted into the socket of a camera, or into an adapter, are well known in the art. A so-called "Magicube" unit of this type contains four mechanically ignitable flashlamps that have protruding igniter tubes and are secured to the base member in operative relationship with four cocked springs for percussively igniting the lamps. The unit also includes a reflector component that defines four individual reflectors for the lamps, and has a cover component of cubical configuration and transparent plastic material that is also fastened to the base member and serves as a protective housing.
The width of such prior art Magicube flash units (that is, the basal edge dimension of the unit along one side) is approximately 30 millimeters and their overall height (the thickness of the base member plus the height of the protective cover) is approximately 34 millimeters. Their width-to-height ratio is thus less than 1. The reflector component employed in such prior art units has a height of approximately 30 millimeters and a width (or basal edge dimension) of approximately 25 millimeters. The spacing of the apex of each of the individual reflector elements from the inner face of the associated side wall of the protective cover is approximately 12 millimeters in each case. The outer bulb diameter of the flashlamps is approximately 9 millimeters, the overall length of the flashlamps (bulb length plus the protruding portion of the igniter tube) is approximately 30 millimeters, and the bulb volume is approximately 0.6 cubic centimeter. The lamp filling comprises zirconium shreds and gaseous oxygen.
A more compact or "miniaturized" multiflash unit of the aforesaid type has been proposed and designed that employs smaller lamps, smaller reflector and base components, and specially-designed lamp-ignition means. The width dimension of this smaller more compact multiflash unit is not more than approximately 24 millimeters and its overall height is not more than approximately 22 millimeters. Its width-to-height ratio is thus equal to or slightly greater than 1. The height of the smaller reflector component is only approximately 17 millimeters and the width dimension (basal edge along one side) is not more than approximately 22 millimeters. The apexes of the individual reflector members are spaced from the inner faces of the associated side walls of the protective cubical cover by a distance of only approximately 9 millimeters in each case. The outer bulb diameter of the flashlamps is approximately 7 millimeters, their overall length (bulb length plus the protruding portion of the igniter tube) is approximately 20 millimeters, and the bulb volume is approximately 0.2 cubic centimeter. The lamps are filled with zirconium shreds and gaseous oxygen. However, either hafnium or yttrium may also be used as the combustible material.
In the standard size prior art Magicube type multiflash units, the dimensional correlation between the flashlamps and associated reflector members is such that the desired radiation intensity and spread of the light rays in the direction in which the picture is being taken is achieved without any additional or auxiliary optical means. The protective plastic cover employed in such prior art units thus has side walls with faces (inner and outer) that are flat and smooth. However, due to the shorter more compact design of the reflector component used in the aforementioned miniaturized multiflash unit, the individual reflector members have a proportionately more intense and greater lateral divergence or spread and produce a corresponding greater lateral spreading or divergence of the light rays when the associated lamps are flashed. The amount of light illuminating the scene being photographed is thus decreased which makes it difficult to obtain pictures of the desired quality.